<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
	</head>
	<body>
		<script type="text/javascript">
		var num=window.prompt("请输入一个数");
		num=parseInt(num);
		temp=num;
		var re=0;
		while(num/10!=0){
			re=parseInt(num%10);
			num=parseInt(num/=10);
		}
		window.prompt(temp+"最高位是"+re);
		</script>
	</body>
</html>
